is a Japanese footballer who plays as a defensive midfielder or right back for club FC Tokyo.
Koizumi started his career as a junior player with Yokohama F. Marinos, but the club did not promote him to their Under-18 team. He entered Ryutsu Keizai University Kashiwa High School and started playing for the school. He subsequently became a regular in the school team that won the Prince Takamado Cup in 2013.
In 2014, Koizumi joined J. League Division 1 club Albirex Niigata and has added some versatility to the Albirex squad. His ability to play in a number of positions across defence and midfield made him an attractive proposition and boss Masaaki Yanagishita was delighted to be able to prise him away from The Big Swan Stadium.
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